For example, there is an electrostatic capacitive touch panel that detects the approach of a finger of a user or the like. This touch panel detects that the finger of the user or the like approaches the touch panel according to a change in electrostatic capacitance of a built-in capacitor (capacitor) (refer to JP-A-2011-33550, for example).
That is, plural transmission electrodes are installed in the touch panel in a row direction, and plural reception electrodes are installed in the touch panel in a column direction in such a manner that the plural reception electrodes respectively intersect with the plural transmission electrodes, for example.
Further, in the touch panel, the approach (referred to as contact in a case where the distance is not present, and proximity adjacency in a case where the distance is present) of the finger of the user or the like is detected at intersection points where the plural transmission electrodes and the plural reception electrodes respectively intersect with each other. That is, in the touch panel, the contact of the finger of the user or the like is detected in a case where the finger of the user or the like approaches the touch panel until the distance becomes D=0, and the proximity adjacency of the finger of the user or the like is detected in a case where the finger of the user or the like approaches the touch panel until the distance becomes D>0.
Specifically, for example, the touch panel applies a drive voltage of square waves to a predetermined transmission electrode, and detects the contact of the finger of the user or the like on the basis of voltage detected in a reception electrode that is connected to the predetermined transmission electrode through a capacitor.
More specifically, for example, if the drive voltage of square waves is applied to the transmission electrode, the voltage of the reception electrode is changed according to the drive voltage applied to the transmission electrode, and is then stabilized into a uniform voltage value. Here, in a case where the stabilized uniform voltage value is equal to or less than a first threshold value, the touch panel detects the proximity adjacency of the finger of the user or the like. Further, in a case where the stabilized uniform voltage value is equal to or less than a second threshold value that is smaller than the first threshold value, the touch panel detects the contact of the finger of the user or the like.
In this regard, time that is necessary until the voltage of the reception electrode is stabilized into the uniform voltage value is proportional to a time constant determined according to a resistor or a capacitor installed in the touch panel. As the time is short, detection time for detecting the approach of the finger of the user or the like is short.